Shingled writing has been proposed as a means to extend the tracks per inch (also referred to as TPI) of magnetic storage. Generally, shingled writing involves sequentially writing partially overlapping tracks with a wide writer. The wide writer can provide higher fields and the sequential shingled writing cuts down the written width and limits adjacent tracks to a single write on one side of the track.
Shingled writing raises numerous concerns. First, writers can suffer from weak fields and gradients near the edge of the track. Second, shingled readback can suffer from transition skew with respect to the reader near the edge of the track. Third, asymmetric writers (which could compensate in part for weak edge field as discussed above) would function for only one skew polarity and would therefore double the maximum skew, and two asymmetric writers would be prohibitively expensive.